Improvement in the manufacture of sheet-iron



SILASl BRKER, OF HARTFORD, CONNECTICUT, SSIGNOR TO HIM- SELF AND HENRY S. PRATT, OF PLACE.

Lehm Patent No. 95,554, daad 0cm-bw 5, 1869.'

IMPRovmm m THE MANUFACTRE' or SHEET-:nou

The Schedule met to in these Letten Patent and making part of the same.

,Manufacture of Sheet-Iron; and Iedeeiare the followin to be a full and exact description thereof;n reference being had to the accompanying and to the letters of reference thereon, forming a part of' this specification. l

.My improvement relates to the mannihcture of a l sheet-iron which sh'all resemble the .so-'called Russia sheet-iron, and have about the same qualities.

I commence with the common article of American sheet-iron, as it is found in commerce, covered with a .black oxide. v0f course, the better the quality ofthe iron to commence with, the vbetter the finished product.

I take this common sheet-iron and immerse it in a bath of acid diluted with water. I have heretofore found it preferable to use a bath of sulphnric acid and water. The proportions differ with each different lot of acid used, as the sulphnric acid of commerce is not at all uniform in strength.

I have 'used six parts of water tol one of acid and still stronger. The only rule that can be given is, to make a weak bath at first, and add more acid, till it will start the black oxide readily from the sheets.

The sheets are left immersed in this bath till the black oxide is all scaled olf The operation can be somewhat assisted by a wire brush.

The black oxide being all-removed, the sheet is then washed thoroughly under a copious jet of water, so that the acid shall be all washed oi.

When the sheet is thoroughly washed of acid, .and while it is yet covered with a film of Water, it is immediately dipped into a bath of potash dissolved in 'wat-er, o1' of water mixed with any of the alkalies.

The purpose of dipping the sheet at this point into thealkaiine 'bath is, first, to neutralize any acid that may possibly still remain on the sheet, and, second, to keep the cleaned sheet 'from contact with the air till itis subsequently rolled.

I am aware, that iu attempts heretofore made to produce l Russia sheet-iron, the sheets have been first dipped inan acidulous bath, and afterward covered with oiL-fresin, andthe like; but to neutralize 'theacid in thislway, and, at the same time, to pre-V `vent any, even the slightest oxidation by such immersion, Ibelieve to be new, and is claimed herein as a par-t of my invention.

In all the methods heretofore followed, as I believe, a yellow oxide has been allowed to gather on the sheet, and has been rolled into the enamel, through which it soon made its appearance, and destroyed the enamel. Instead of cleaning the sheets by-an acid bath, as

yjust described, they may be mechanically cleaned, by grinding or polishing, and'then A,immediately dipped into the alkaline bath.

Whichever way they are cleaned, they remain inrmersed in the alkaline bath till taken out for rolling, be the time elapsing more or less.

A number of these sheets, say twelve or twenty, having reached this point, rare piled together in a pack, and rolled. v

The rolls, between which the pack isl rolled, are shown in figs. 1 and 2, on Sheet No. 1 of the accompanying drawings. Y l

Y Figure 1 is a sectional'elevat-ion, and

Figure 2, a perspective-view.

The letter a. designates one roll, the letter b, the other.

Theupper or the under roll, preferably the under, is'driven by power, While the other is loose. Although not so shown, the 'rolls are, as a matter ofcourse, ad-

instable np and1 down in their bearings, for the purpose of allowing thedistance betweenf the rolls to be regulated at pleasure j These rolls are made of chilled iron, or some proper substitute therefor, and have irregular or pitted-surfaces. 'I make the rolls by rst turning a wooden roll of the right size, then taking a piece of sheet-zino,

which will just go around the roll, and.indenting its surface with a. blunt-pointed, round` punch, till the raised and the depressed parts of the surface are about egual, and then fastening the zinc around the roll. It

will now servefor a pattern, from which cast-iron moulds, for casting chilled rolls, cau be made in the usual wav.

- The chilled rolls having been properly made and arranged for work, the pack of 'sheets is taken from the alkaline bath and rolled between them, till the surfaces of the sheets are properly enamelled. The irregular character of the surfaces of the rolls serves to give the sheets the .ham mered appearance of the genuine Russia, and, at the same time,tl1oroughly polishes the sheets.

I am well aware that rolls, with mottled surfaces, have been used for this purpose heretofore, but they have not been made inl such a way as to have the surfaces ofthe rolls irregular and yet smooth at lthe same time, as is the case with my rolls.

The o`utsides of the sheets of the pack, that is, those next the rolls, will not be polished on both sides, and have to be put into the middle of thenext pack and rolled again.

The sheets, being properly enamelled, are then pnt into an oven, shown in figs. 1 and 2, on Sheet No. 2 of the accompanying drawings.

Figure 1 is a cross-section.

Figure 2 is a lengthwise section.

The letters b and b designate .the sides of the oven, made of fire-blick, with fire-spaces between them and the outside walls c and c.

l is the furnace, and

e is the top of the oven, also made of Ere-brick.

The bottom of the oven, f, is a plate of cast-iron, so as to radiate the hea-t freely into the oven.

The oven is closed on all sides from direct contact with the dame.

g is the back of the oven, made of fire-blick, and

h is the door, which has an aperture in it, set with glass, through which light Iuay be thrown, so as to see the sheets when desired.

v The letters t' t i, designate sliding meta-1 rods, more or less iu number, two (2) upon the same plane, which draw out at the side, by means of the handles 'i' t'. v

The sheets are taken, after rolling, and placed in this oven, upon the rods, 'and they )vill thus be entirely separated, one from 'the other, so that the heat will touch all points alike.

The sheets are shown thus placed upon the rods, and are designated by the letters k k 7c.

The oven is now evenly and carefully heated, till i the sheets are thoroughly annealed, and till they have attained the fine blue color of the genuine Russia,

when the rods supporting the upper sheet are pulled, and the sheet dropped down on to the one below it, and so on, till all the sheets are again in a pack,' when they are taken from the oven and passed once or twice through the rolls, to restore the enamel, which may have been slightly disturbed in annealing, and the process is finished. f

Instead of taking the pack from the alkaline bath and rolling it cold, it may be taken from the bath and heated, in the oven just described, not above 'adull red heat, and then rolled Vtill properly enamelled, when the sheets will need to be blued in the oven, and the process is finished.

I claim, as my invention- The process, herein set forth, of Russia sheet-iron.

Also, the rolls, made by the process and in theH manner described, and used for the purpose set forth;

Also, the oven, made as described, with the sliding rods, or their equivalents, and used for the purpose set forth. f

making imitation SILAS BARKER. Witnesses:

W. EDGAR SrMoNDs, HENRY S. Piwrrg 

